Vam6 reduces iNKT cell function in tumor via modulating AMPK/mTOR pathways

Motility and tumor infiltration are key aspects of invariant natural killer T cell anti-tumor function

Dysfunction of invariant natural killer T (iNKT) cells contributes to immune resistance of tumors. Most mechanistic studies focus on their static functional status before or after activation, not considering motility as an important characteristic for antigen scanning and thus anti-tumor capability. Here we show via intravital imaging, that impaired motility of iNKT cells and their exclusion from tumors both contribute to the diminished anti-tumor iNKT cell response. Mechanistically, CD1d, expressed on macrophages, interferes with tumor infiltration of iNKT cells and iNKT-DC interactions but does not influence their intratumoral motility. VCAM1, expressed by cancer cells, restricts iNKT cell motility and inhibits their antigen scanning and activation by DCs via reducing CDC42 expression. Blocking VCAM1-CD49d signaling improves motility and activation of intratumoral iNKT cells, and consequently augments their anti-tumor function. Interference with macrophage-iNKT cell interactions further enhances the anti-tumor capability of iNKT cells. Thus, our findings provide a direction to enhance the efficacy of iNKT cell-based immunotherapy via motility regulation.

Antigen Priming Induces Functional Reprogramming in iNKT Cells via Metabolic and Epigenetic Regulation: An Insight into iNKT Cell-Based Antitumor Immunotherapy

Dysfunction of intratumoral invariant natural killer T (iNKT) cells hinders their antitumor efficacy, but the underlying mechanisms and the relationship with endogenous antigen priming remain to be explored. Here, we report that antigen priming leads to metabolic reprogramming and epigenetic remodeling, which causes functional reprogramming in iNKT cells, characterized by limited cytokine responses upon restimulation but constitutive high cytotoxicity. Mechanistically, impaired oxidative phosphorylation (OXPHOS) in antigen-primed iNKT cells inhibited T-cell receptor signaling, as well as elevation of glycolysis, upon restimulation via reducing mTORC1 activation, and thus led to impaired cytokine production. However, the metabolic reprogramming in antigen-primed iNKT cells was uncoupled with their enhanced cytotoxicity; instead, epigenetic remodeling explained their high expression of granzymes. Notably, intratumoral iNKT cells shared similar metabolic reprogramming and functional reprogramming with antigen-primed iNKT cells due to endogenous antigen priming in tumors, and thus recovery of OXPHOS in intratumoral iNKT cells by ZLN005 successfully enhanced their antitumor responses. Our study deciphers the influences of antigen priming-induced metabolic reprogramming and epigenetic remodeling on functionality of intratumoral iNKT cells, and proposes a way to enhance efficacy of iNKT cell-based antitumor immunotherapy by targeting cellular metabolism.